Problem: $ { \left[\begin{array}{r}{0} \\ {0} \\ {4}\end{array}\right]+\left[\begin{array}{r}{-1} \\ {0} \\ {4}\end{array}\right] = {?} } $
Solution: To find the sum of two matrices, add the corresponding items between each matrix. ${\left[\begin{array}{r}{0}+{-1} \\ {0}+{0} \\ {4}+{4}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{r}{-1} \\ {0} \\ {8}\end{array}\right]}$